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Interest in Wireless Sensor Network AppMod? — Parallax Forums

Interest in Wireless Sensor Network AppMod?

Martin HebelMartin Hebel Posts: 1,239
edited 2006-09-21 13:26 in BASIC Stamp
Hi All,
For research, I've been working with the XBee ZigBee/802.15.4·module·(though not full ZigBee for those in the know).
http://www.maxstream.net/products/xbee/xbee-oem-rf-module-zigbee.php

This is a wireless networking device using the 802.15.4 protocol (for example, Bluetooth is 802.15.3).· These units are ideally suited to wireless sensor networks.· Some of the key features are:

- TX/RX at 250kbps
- Individually accessed by unit address or broadcasts to all (up to 64K addresses)
- Very low sleep current (<10uA)
- Use clear channel assessment and acknolwedgements to help ensure data delivery.
- Data is buffered so the BASIC Stamp may use the RTS line to read data when ready.
- Groups can be defined by personal area network ID (PAN ID) or by channel.
- 2.4GHz operating frequency
- Distances up to 1 mile (ok, it'd have to be very high and total line of sight, but possible with the 100mW version - Xbee Pro).
- Very easy to configure and send/receive data from the BASIC Stamp - see attached code for sample
- Measure of signal strength in dBm
- Fully configurable with AT commands.
- Ability to change addressing on the fly.

We've developed an App-Mod for the Board of Education.· It uses jumpers to select the I/O and features of the Xbee to use, though all that's really needed for the board are:
-VIN
-Vss
-TX
-RX
-RTS for flow control

It also allows connections to many other features of the XBee such as sleep modes, network associations and measuring signal strenth (can be done with serial AT codes also).· The device is 3.3V, so the board has a 3.3V regulator and a 5V to 3.3 buffer for BASIC Stamp outputs.· Also,·the XBee·uses 2mm pin spacing so it is NOT breadboard-able.

I am conducting testing in ag fields, but they also have great possibilities in all kinds of sensing and control applications including robotics, and teaching networking.

I'm working on a Nuts N Volts article for it, and I'm wondering about the interest in the board.· I'd sure like to make these available to interested parties, and while I'll release the PCB files and parts list when ready, many may want something ready to use.· In calculating costs, here's what I'm considering:
4 boards only (no parts) for $50.
1 board with parts & 1mW Xbee, solder yourself·- $70
1 board with 1mW Xbee, soldered ready for use - $90.

Also, a USB2SER may be plugged into the header for a direct link to the PC via a terminal program or other software.· The XBEE is firmware upgradeable, though it requires a more complex interface than provided here.· I'll upgrade the firmware before shipping.

So, here's some Q's:
Q: Is there any interest in the board?
Q: Should I have the full I/O jump-able using the 20 pin app-mod header (makes it more expensive by about $6), or simply use a·5 pin header to plug into the breadboard (so it can be used with other boards too - Homework Board).· Not sure about the weight on the 5 pins yet though.

I tired the eb500, and never cared much for it.· This device is very cool, very easy, and easy to use since the protocol is designed more for the this type of communications than bluetooth.· I've held a workshop recently with 8 devices being able to access·or control each one individually, or as a group.· I also have a board for the Propeller header, though much simpler since the prop is 3.3V to start with.

Thanks for any input or feedback,
Martin




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Martin Hebel
Southern Illinois University Carbondale - Electronic Systems Technologies

Personal Links with plenty of BASIC Stamp info
StampPlot - Graphical Data Acquisition and Control

Post Edited (Martin Hebel) : 8/15/2006 3:45:11 AM GMT
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